Adeno-associated virus (AAV) is a single stranded DNA virus with broad host range that commonly infects humans but produces no disease. Replication of AAV requires co-infection with a complementing virus, usually adenovirus. AAV vector preparations have been obtained using a recombinant plasmid containing the terminal inverted repeat structures of AAV flanking a specific transcriptional unit. Co-transvection of tissue culture cells with this plasmid and a second helper plasmid containing the structural genes for AAV proteins after infection with wild-type adenovirus results in the release of AAV vector particles without wild-type virus production. Previously we have shown that the Agamma globin gene linked to HS2 from the globin locus control region (LCR) exhibits regulated, high level expression when integrated into the genome of human erythroleukemia (K562) cells. Now we have shown that usually but not invariably, a single copy of the viral genome is integrated and that NF-E2 but not GATA-1 binding to HS2 is required for inducible expression. AAV mediated gene transfer into primary, enriched primate progenitors has been verified by detection of site specific integration of wild-type AAV into chromosome 19. A vector containing HS4, HS3, and HS2 linked to the Agamma globin gene has been shown to transfer and express this gene in primary hematopoietic cell. Finally, a vector containing the FACC gene known to be defective in a subset of patients with Fanconi's anemia has been shown to transfer and express this gene in patient cells thereby correcting the defect in DNA repair and cell proliferation.